Question

(a) The far point of a myopic person is `80 cm`. In front of the eye. What is the power of the lens required to enable him to see very distant objects clearly ?
(b) In what way does the corrective lens help the person above ? Does the lens magnify very distant objects ? Explain carefully.
( c) The person above prefers to remove his spectacles while reading a book. Explain why ?

Answer 1

Distance of afr point, `x = 80 cm, P = ?`
For viewing distant objects, focal length of corrective lens, `f = -x = -80 cm`
Thus, `P = (100)/(f) = (100)/(-80) = -1.25 D`. The lens in concave.